Pregnancy and Group B Strep Prevention
How Will I Know if I Need Antibiotics to Prevent Passing Group B Strep to My
Baby?
You should get a screening test late in pregnancy to see if you carry group B strep. If your
test comes back positive, you should get antibiotics through the vein (IV) during labor. If
you had a previous baby who got sick with group B strep disease, or if you had a urinary
tract infection (bladder infection) during this pregnancy caused by group B strep, you also
need to get antibiotics through the vein (IV) when your labor starts.
How Do You Find Out if You Carry Group B Strep During Pregnancy?
The Center for Disease Control and Prevention’s (CDC) revised guidelines recommend that a
pregnant woman be tested for group B strep in her vagina and rectum when she is 35 to 37
weeks pregnant. The test is simple and does not hurt. A sterile swab (“Q-tip”) is used to
collect a sample from the vagina and the rectum. This is sent to a laboratory for testing.
What Happens if My Pregnancy Screening Test Is Positive for Group B Strep?
To prevent group B strep bacteria from being passed to the newborn, pregnant women who
carry group B strep should be given antibiotics through the vein (IV) at the time of labor or
when their water breaks.
Are There Any Symptoms if You Are a Group B Strep Carrier?
Most pregnant women have no symptoms when they are carriers for group B strep bacteria.
Sometimes, group B strep can cause bladder infections during pregnancy, or infections in
the womb during labor or after delivery.
Being a carrier (testing positive for group B strep, but having no symptoms) is quite
common. Around 25 percent of women may carry the bacteria at any time. This doesn’t
mean that they have group B strep disease, but it does mean that they are at higher risk for
giving their baby a group B strep infection during birth.
What if I Don’t Know Whether or not I Am Group B Strep Positive When My Labor
Starts?
Talk to your doctor about your group B strep status. Pregnant women who do not know
whether or not they are group B strep positive when labor starts should be given antibiotics
if they have:
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Labor starting at less than 37 weeks (preterm labor);
Prolonged membrane rupture (water breaking more than 18 hours before labor
starts);
Fever during labor
What Are the Risks of Taking Antibiotics to Prevent Group B Strep Disease in My
Newborn?
Penicillin is the most common antibiotic that is given. If you are allergic to penicillin, there
are other antibiotics that can be given. Penicillin is very safe and effective at preventing
group B strep disease in newborns. There can be side effects from penicillin for the woman,
including a mild reaction to penicillin (about a 10 percent chance). There is a rare chance
(about one in 10,000) of the mother having a severe allergic reaction that requires
emergency treatment.
However, a pregnant woman who is a group B strep carrier (tested positive) at full-term
delivery who gets antibiotics can feel confident knowing that she has only a one in 4000
chance of delivering a baby with group B strep disease. If a pregnant woman who is a group
B strep carrier does not get antibiotics at the time of delivery, her baby has a one in 200
chance of developing group B strep disease. This means that those infants whose mothers
are group B strep carriers and do not get antibiotics have over 20 times the risk of
developing disease than those who do receive treatment.
Can Group B Strep Cause Stillbirth, Pre-Term Delivery or Miscarriage?
There are many different factors that lead to stillbirth, pre-term delivery or miscarriage.
Most of the time, the cause is not known. Group B strep can cause some stillbirths, and preterm babies are at greater risk of group B strep infections. However, the relationship
between group B strep and premature babies is not always clear.
Will a C-Section Prevent Group B Strep in a Newborn?
A C-section should not be used to prevent early-onset group B strep infection in infants.
If you need to have a C-section for other reasons, and you are group B strep positive, you
will not need antibiotics for group B strep only, unless you begin labor or your water breaks
before the surgery begins.
What Should I Do if My Water Breaks Early?
If your water breaks before term, get to the hospital right away. If your group B strep test
has not been done, or if you don’t know if you have been tested, you should talk with your
doctor about group B strep disease prevention. If you have tested positive already for group
B strep, remind the doctors and nurses during labor.
Can I Breastfeed My Baby if I Am Group B Strep Positive?
Yes. Women who are group B strep positive can breastfeed safely. There are many benefits
for both the mother and child.
Source: National Center for Immunization and Respiratory Diseases, Centers for Disease
Control and Prevention
Updated: April 2008